Knife sharpener



Oct. 30, 1956 w. H. JEROME ET AL 7 KNIFE SHARPENER Fiied July 16, 1954 ZZHQZIZWRS WALLACE 6- JERd/Vi MEL w J. JENSEN United States Patentfififiee 2,768,476 iiateatedoet. :-3o,-.-r 956 This invention relates to a grinding apparatus and more --particularly'to a self-dressing knife sharpener.

It is a general object of the invention to provide an economical and efficient knife sharpening devicewhich will be long-lasting and which will require but a minimum of maintenance.

-More-specifically, it is an 'objectof'the invention to provide a sharp'eningdevice having a pair offigrinding wheels for simultaneously grinding and sharpening at both sides of a -knife' edge and-which Wheels 'rnay'be movedinto contacting relation for self-dressing.

It isa' further object of the inventionto provide a sharpening'device of the class described in' which peripherally aligned grinding wheels are'operated atsomewhat diiferent speeds to effect proper simultaneous-edge sharpening of knives and the like, and having 'sufiicient relative movement between contacting surfaces to produce self-dressing when the wheels are moved into contacting relation.

Still more specifically, it is an object of the invention to provide a sharpening-device having a pair of grinding Wheels positioned by adjusting-mechanism and driven .by a powered-belt, wbich'adjusting mechanism can be moved to tighten the belt 'as well asto adjust clearances and dressing contact between the respective wheels.

These and other objects and advantages of the invention will more fully appear from the following description made in connection with the accompanying drawings, wherein like reference characters refer=to the same or similar parts throughout the several views, and inWhich:

P Fig. '1 is a top plan view of our-knife sharpening-device; and

Fig. 2 is a side elevation of the device, certain portions being cut away invertical section and-others which are 1 hidden from View being shown in dotted linestructure.

With continued reference to the drawing, Fig. 1 shows a top plan view of our device in which a mounting structure is indicated generally at 10. On the mounting structure is supported a pair of bearing members 11 and 12 which in turn are mounted for transverse adjustment. The bearing member 11 is preferably slidably arranged on an upstanding element 13 and the bearing member 12 is formed rigidly with element 13 and has a lower face 12a which is slidably arranged with respect to the base of the mounting structure 10, bolts 12b being threadably received into face 12a and adjustably slidable in slots 16a through base 10, one of which slots is shown in fragmentary section in Fig. 2. Each of the bearing members 11 and 12 are adapted to slidably converge and diverge and are adjustable by means of the manually operable screws 14 and 15 respectively. The screws 14 and 15 have knob members 16 and 17 secured to the outer ends and are threadably received within upstanding brackets 18 and 19 which are respectively secured to the base with the manual adjustment screws 14 and positioned in opposition as shown in Figs. 1 and 2. The inner end of adjustment screw 14 is rotatably received within the outside of bearing member 11 so that the bearing celementizcanbe: moved to I the left' or the 'right as viewed in Figs. 1 and 2, andthe threaded memberv 15 'is' rotatably mounted on the upstanding bracket 19 with itsrthreaded'outer end received within the bearing mem- "'ber 12tso that the entire bearing member 12 "and bearing llimounted thereon can be adjustably moved to the left or to the rightin' relationwith the base 10.

Rotatably journal'edin the'bearing -11is the-grinding wheel -20, the axialshaft 21 being'secured .to the'grinding wheel by means of nut 22 and extending inwardly through the bearing -1Ftoeterminate in an endextension 23 to whic-his attached 'ardrive wheel 24 by means of'set screw 24a asshown'in Fig: 1. 77A collar 25 is securedto sh'aft 21 between theygrinding'wheel "and the bearing 'member 11 by means ofset 'screw 26.

- In a similar manner, angrinding wheel 27 is mounted on a shaft 28;" t'=he "outer": endof which is threaded to receive/abut 29rfor=holding the grinding wheelin rigid relation therewith-,-cand the shaft -28-extends through beara-drive wheel 31'by means of set screw 31a. Thedrive wheels! isof'tdifferent diameter than that of the "drive wheel.24 andfin-theinstant case,"is slightly larger than '-its-=associatedsdrive-wheel 24. The drive-wheels 24 "and ing :12 toterminate-in'aninner end to which is attached '31 are insspaeednparallel relation and in alignment for '-driving, as=-will -besubsequently described. A collar 'member 32 is secured to the.shaft-28-between the grinding wheel 27 and the bearing 12 by-such means-asset; screw 33, as shown in Fig. l.

Rearwardly of the bearing members 11 and 12 and in driving alignment with the wheels 24 and 31 is. a'drive- 4 standing portion 13 by means ofdepending :fiange 41 .throughwhich studbolts "42 and 43 extend, and asecond --member 44 which is likewise slidably mounted beneath "the first member 40 and having a depending flange) 45 slidably mounted on the same stud members 42 and 43.

Further guidemeansrearwardly of the grinding wheels '20 and 27 comprises a U-shaped upstanding bracketf46 which is attached by'such means as screws47 to the vupstanding bracket 13, the upper ends-of which constitute upwardly diverging plates 48 and'49 which are positioned in spaced relation, as shown in Figs. 1 and 2.

In the use and operation of our invention, the grinding wheels 20 and 27 are positioned in close clearance so that the outer cylindrical grinding surface of each of the Wheels is in opposition, as shown in Fig. 1. The motor 38 is then energized so as to rotate in a counterclockwise direction as viewed in Fig. 2 with grinding wheel 20 rotating also in a counterclockwise direction while the grinding wheel 27 rotates in a clockwise direction. Because the driving wheel or pulley 31 is of slightly larger diameter than the drive wheel 24, the grinding wheel 27 will rotate at a slightly slower speed than grinding wheel 20. However, since a knife to be sharpened is held rigidly between the adjustable guide member 4849 and the forward adjustable guides 39, the knife edge will be evenly sharpened at both sides to produce a keen edge. The adjustable screws 14 and 15 may be operated so that the bearing member 11 and bearing member 12 can be moved by screw 15 alone to the left as viewed in Fig. 2 to tighten the belt 34 and still to maintain the proper clearance between grinding wheels 20 and 27 by adjusting screw 14. Where a thinbladed knife is to be ground, the wheels 20 and 2.7 are in a clearance which amounts only to a slight degree, in the order of a few ten-thousandths of an inch. Side play of the knife to be sharpened (not shown) will effect a proper edge grinding so that the finished job will presenta keen and sharp edge.

When the grinding wheels 20 and 27 acquire an irregular cylindrical grinding surface and when they become filled with steel and impurities so as to reduce the efficiency of the grinding wheels, then it becomes necessary to dress the wheels to re-establish the proper degree of grinding for the purposes described. Whereas dressing tools are used on ordinary grinding equipment to re-shape and resurface the grinding wheels, our invention contemplates the self-dressing of the grinding wheels by coaction between the surfaces thereof while operation at different rates of speed. Thus it is only necessary to relatively converge the grinding wheels 20 and 27 so that v the cylindrical grinding surfaces come into contact to effect the dressing operation. It will be remembered that grinding wheel 20 operates at a slightly greater speed than that of wheel 27 and hence there is relative movement between the wheels even though they operate in opposite directions with their opposed surfaces traveling in the same upward direction. This relative travel wherein the grinding wheel 20 rotates faster than grinding wheel 27, will produce a grinding effect between the relative cylindrical surfaces and thereby cause the steelfilled areas as well as uneven areas upon the cylindrical surface to be dressed down and to re-establish the original shape and quality of the cylindrical grinding surface. When the proper degree of dressing has been accomplished, the adjusting screw 14 is moved in a direction transverse to the axis of grinding wheel 20 and the adjusting screw 15 is likewise moved transversely to the axis of grinding wheel 27 to effect the proper clearance between grinding wheels 20 and 27. If the flexible belt 34 is not sufiiciently tight to properly operate the two grinding wheels, the adjusting screw 14 may be further retracted followed by relative converging of adjusting screw 15 to re-establish the proper clearance between the grinding wheels and at the same time to tighten the flexible belt 34.

It will be understood, of course, that the guide element 39 can be adjusted properly so that the V-shaped medial area will be in proper alignment with the closest peripheral line existing between the grinding wheels 20 and 27.

It may thus be seen that we have devised a knife sharpening device in which the grinding elements constitute rotary wheels in contacting or in close clearance for the purpose of properly grinding an edge on knives and other similar tools, while at the same time operating at slightly difierent speeds so that the wheels may be moved into contact for the purpose of dressing the peripheral or cylindrical surfaces and re-establishing the proper grinding characteristics at intervals during the life of the equipment.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of our invention.

What we claim is:

1. A powered knife sharpener comprising, a mounting base, a motor rigidly mounted on said mounting base, a bearing member mounted for sliding adjustment on said mounting base with the axis of said bearing in spaced parallel relation with that of the motor, a second bearing mounted for sliding adjustment of said first bearing, the axis thereof lying in spaced parallel clearance with that of the motor and said first bearing, a shaft having a drive wheel and a grinding wheel in opposed relation rotatably journaled in said first bearing, a shaft having a drive wheel and a grinding wheel in opposed relation rotatably journaled in said second bearing, the plane of said grinding wheels and of said drive wheels being respectively the same, driving means connecting said motor with said drive wheels, means mounted on said mounting base in engagement with said first bearing for adjusting said first and second bearings simultaneously with respect to the base, and means on said first bearing and in engagement with said second bearing for adjusting the second bearing independently with relation to the first bearing whereby to maintain driving connection with said motor and at the same time adjust the relative positions of said grinding wheels.

2. The subject matter set forth in claim 1 wherein the driving means is a belt connection with the motor, the belt passing under the drive wheel on the shaft mounted in the first bearing and around the drive Wheel on the shaft in the second bearing whereby the adjusting means mounted on the base will tighten the belt simultaneously with respect to both of said drive wheels and the adjusting means in engagement with the second bearing will independently adjust the clearance between said grinding wheels.

References Cited in the file of this patent UNITED STATES PATENTS 22,781 Cave Feb. 1, 1859 196,333 Capewell Oct. 23, 1877 631,842 Worden Aug. 29, 1899 654,215 Worden July 24, 1900 1,772,932 Einstein Aug. 20, 1930 1,958,001 Heim May 8, 1934 

